Formic acid or HCOOH is a colorless liquid with a pungent odor. It is widely used as a preservative, antibacterial agent, and in the manufacturing of leather, textiles, and rubber.
| IUPAC Name | Methanoic acid |
| Molecular Formula | HCOOH |
| CAS Number | 64-18-6 |
| Synonyms | Hydrogen carboxylic acid, formylic acid, aminic acid, formylic acid, metacarbonoic acid, thionyl formic acid, and more. |
| InChI | InChI=1S/CH2O2/c2-1-3/h1H,(H,2,3) |
Formic Acid Structure
The structure of formic acid is characterized by a carboxylic acid group (-COOH) attached to a single carbon atom. The carbon atom is also bonded to a hydrogen atom and an oxygen atom. The structure of formic acid is planar, and it exhibits hydrogen bonding between the carboxylic acid groups. The hydrogen bonding gives rise to its high solubility in water.
Formic Acid Formula
The chemical formula of formic acid is HCOOH. It is a simple organic compound that contains one carbon atom, one oxygen atom, and two hydrogen atoms. The formula of formic acid is important in determining its chemical and physical properties, as well as its behavior under different conditions. It is also used in various chemical calculations, such as stoichiometry and molarity.
HCOOH Lewis Structure
The Lewis structure of formic acid (HCOOH) is as follows:
H
|
C=O
|
OH
The carbon atom is in the center of the structure with four valence electrons. It forms single bonds with the two hydrogen atoms and the oxygen atom, which has two lone pairs of electrons. The oxygen atom also forms a double bond with the other carbon atom, which carries one lone pair of electrons. The Lewis structure shows that the molecule has a polar covalent bond due to the difference in electronegativity between the carbon and oxygen atoms.
Formic Acid Molar Mass
The molar mass of formic acid, also known as methanoic acid, is 46.03 g/mol. It has a chemical formula of HCOOH, which indicates that it contains one carbon, one oxygen, and two hydrogen atoms. The molar mass is an important parameter in determining the amount of a substance required to make a solution of a specific concentration. For example, to prepare a 1 M solution of formic acid, one would need to dissolve 46.03 g of formic acid in 1 liter of solvent.
Formic Acid Boiling Point
The boiling point of HCOOH is 100.8 °C (213.4 °F). It is a colorless liquid that has a pungent odor, and it is highly soluble in water. The boiling point of HCOOH is relatively low, which means that it can be easily vaporized and distilled. This property makes it useful in various industrial applications, such as the production of dyes, plastics, and pharmaceuticals.
HCOOH Melting Point
The melting point of HCOOH is 8.4 °C (47.1 °F). It is a solid at room temperature, and it can be obtained in its pure form by cooling it below its melting point. HCOOH crystals are white and have a sharp odor. The melting point of HCOOH is relatively low compared to other carboxylic acids, which makes it a useful solvent for certain chemical reactions.
HCOOH Density g/mL
The density of HCOOH is 1.220 g/mL at 25 °C (77 °F). It is denser than water, which has a density of 1.000 g/mL at the same temperature. The density of HCOOH is an important property that determines its solubility in water and other solvents. It also affects its behavior under different conditions, such as temperature and pressure.
Formic Acid Molecular Weight
The molecular weight of formic acid is 46.03 g/mol. It is a simple organic compound that has a chemical formula of HCOOH. Molecular weight is an important parameter in determining the physical and chemical properties of a substance. It is used to calculate various quantities, such as the number of moles, mass, and volume of a substance.
| Appearance | Colorless liquid |
| Specific Gravity | 1.22 |
| Color | Colorless |
| Odor | Pungent |
| Molar Mass | 46.03 g/mol |
| Density | 1.220 g/mL |
| Melting Point | 8.4 °C |
| Boiling Point | 100.8 °C |
| Flash Point | 68 °C |
| Water Solubility | Miscible |
| Solubility | Soluble in most organic solvents |
| Vapour Pressure | 44.5 mmHg |
| Vapour Density | 1.5 (air=1) |
| pKa | 3.75 |
| pH | 2.4 |
Formic Acid Safety and Hazards
HCOOH poses several safety and hazard risks. It is a highly corrosive and toxic substance that can cause severe skin burns and eye damage upon contact. Inhalation of HCOOH vapors can result in respiratory irritation and damage to the lungs. It is also flammable and can ignite at high temperatures, posing a fire hazard. Proper safety precautions should be taken when handling HCOOH, including the use of protective clothing, gloves, and eye protection. It should be stored in a cool, dry, and well-ventilated area, away from incompatible materials, such as oxidizing agents and alkalis.
| Hazard Symbols | Corrosive, Toxic |
| Safety Description | Wear protective gloves and eye/face protection. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. |
| UN IDs | UN1779 |
| HS Code | 2915.11.00 |
| Hazard Class | 8 (Corrosive) |
| Packing Group | II (Intermediate) |
| Toxicity | LD50 1.8 g/kg (oral, rat) |
Formic Acid Synthesis Methods
Formic acid can be synthesized by various methods.
- One common method involves the reaction of carbon monoxide and water in the presence of a catalyst, such as rhodium or cobalt. This is formox process. This process produces formic acid and hydrogen gas.
- Another method involves the oxidation of formaldehyde using a strong oxidizing agent, such as chromic acid or potassium permanganate, under acidic conditions. This reaction produces formic acid and water.
- One way to synthesize formic acid is by reacting sodium formate with sulfuric acid. This reaction results in the formation of formic acid and sodium sulfate as a byproduct.
- Ants produce formic acid as a natural defense mechanism, and it can be obtained from their bodies through distillation.
- Another method of HCOOH synthesis is through the reaction of carbon dioxide with hydrogen in the presence of a catalyst, such as copper chromite or zinc oxide. This process, known as the HCOOH synthesis reaction, produces HCOOH and water.
- HCOOH can also be obtained from natural sources, such as the leaves of stinging nettle, where it is present in small quantities.
Overall, there are several methods available for the synthesis of HCOOH, each with its advantages and disadvantages.
Formic Acid Uses
Formic acid has a wide range of applications in various industries.
- Its ability to prevent the growth of harmful microorganisms makes formic acid a common choice as a preservative and antibacterial agent in animal feed and silage.
- It helps prevent the growth of harmful microorganisms in animal feed and silage, making it a useful additive.
- The textile industry uses formic acid as a dyeing and finishing agent for fabrics to improve color fastness and increase the affinity of dyes to fibers.
- Formic acid serves as a solvent and intermediate in the production of various chemicals like acetic acid, formamide, and methanol.
- Formic acid is a tanning agent in the leather industry that helps improve the texture and durability of leather products.
- In the production of rubber, formic acid facilitates the process of vulcanization by serving as a coagulant.
- The pharmaceutical industry uses formic acid as a preservative for vaccines and as a disinfectant for medical equipment.
- In addition, formic acid finds application in the production of various medicines, including diuretics and antihistamines.
- Formic acid is a reducing agent in organic synthesis reactions and a catalyst in polymerization reactions.
- Formic acid helps enhance the aroma of various products, making it useful in the production of flavors and fragrances.
Overall, formic acid’s diverse range of applications across various industries is due to its unique properties and versatile nature.
Questions:
Q. Is formic acid a strong acid?
A. Formic acid is a weak acid, with a pKa value of approximately 3.75. This means that it does not fully dissociate in water and is a weaker acid compared to strong acids such as hydrochloric acid or sulfuric acid.
Q. Which is more acidic formic or acetic acid?
A. Formic acid is more acidic than acetic acid. This is due to the presence of a methyl group in acetic acid which stabilizes the negative charge on the conjugate base, making it less likely to dissociate. On the other hand, formic acid has a smaller molecular size and a stronger electronegative atom (oxygen), which makes it easier to dissociate, making it more acidic.
Q. Formic acid is produced by which ant?
A. Formic acid is produced by several species of ants, including wood ants, fire ants, and some species of stingless bees. The acid is stored in the ant’s body and is used as a defense mechanism against predators. When threatened, the ant can spray formic acid from its stinger or release it from specialized glands in its body.